Commercial electricity is typically generated by turbines driven by steam. Sources of heat to produce this steam include burning fossil fuels and nuclear fission. However, both of these methods of producing electricity involve significant environmental risks. Consequently, there is a need for renewable, pollution free alternatives to fossil and nuclear fuels. Additionally, most current clean energy alternatives such as wind power have come under fire for being too large, noisy, being an eyesore, or for killing wildlife, with people along the coasts and elsewhere complaining about their installation.
One such environmentally sound method without these drawbacks is the use of ocean or other body of water's waves to generate electricity. More particularly, it is known to convert the mechanical energy of oscillating ocean waves into electricity via an electric generator. Examples of such applications include those of U.S. Pat. Nos. 7,319,278; 5,066,867; 5,176,552; 7,245,041; 6,695,535; 4,340,821; 4,242,593; 4,228,360, and U.S. Application No. 2004/0061338, which all disclose methods of converting ocean wave power into electricity. These patents and patent applications, however, disclose buoys which will float away to the furthest extent of their cables, leaving the devices unable to generate significant amounts of power. Additionally, some of these patents leave the devices open to corrosion and damage from sea life, and unable to withstand the forces of hurricanes, storms and other events. They also can not move with relation to the average height of the surface of the water to reduce stress on the devices during extreme weather events or water level rise due to global warming. The devices do not have warning lights to warn ships away, nor do they have highly visible coatings to protect them from the elements and to warn away wildlife. The above patents also do not disclose the use of a plurality of generators per device which all work on both the rise and fall of each wave, which would significantly increase their efficiency. If using only a single generator, these devices cause gears to turn, which turn either a flywheel or generator downstream. All these devices have multiple gears, clutches, separate flywheels, and other similar devices, all of which reduce the efficiency of the system.
U.S. Pat. No. 5,176,552, for example, discloses methods of converting ocean wave power into electricity using a buoy and a metal disk which creates drag as the buoy rises. This motion causes a pull on a string, which stretches a spring to turn gears for electrical generation. As the first wave rises, the drag may create some energy, but the disc must fall all the way back down to get much energy out of the next wave, which is unlikely. This creates an energy loss in the system and reduces its efficiency. Secondly, the length and strength of the spring takes even more energy out of the system as the wave must first travel the length of the spring before imparting any energy to the device. The strength of the spring, which will lessen over time, also drastically limits the amount of energy that can be generated. Additionally, it does not use gravity as a counterweight, greatly reducing efficiency. Finally, the embodiments of this patent only generate energy as a wave rises, not as it falls, leaving only part of half of the wave to generate electricity which is extremely inefficient.
U.S. Pat. No. 4,159,427 uses propeller blades to convert a fluid flowing in a preferred direction into electricity. This means that the fluid must be traveling in the preferred direction in order to gather that energy.
U.S. Pat. No. 3,818,704 converts surface waves into electricity by spinning a float positioned on the surface of a body of water. It requires that the float be mounted on the surface of the water, exactly at the height of the top of the waves. Since the height of waves differ depending on a variety of factors, it is unlikely to gather much energy at all, especially depending on the height of the tide. What energy the invention in U.S. Pat. No. 3,818,704 does gather is also reduced by the gears it must turn in order to turn the generator.
U.S. Published Patent Application No. 2009/0072540 does use both upward and downward motion of waves to generate electricity. However, the electricity is generated using gears, which significantly reduces the amount of energy transmitted to the generator(s). It also uses two different generators, one in the up direction, one in the down direction to generate electricity which stops all momentum at the top and bottom of each wave, reducing efficiency, and therefore and electricity produced. U.S. Published Patent Application No. 2009/0072540's single-generator design is also open to the elements which make it extremely vulnerable to corrosion and sea life growing on it, preventing the gears from turning. It also does not use gravity as a counterweight, reducing efficiency.
To this end, there is a need for a wave powered electricity generating device that is able to maximize capture of energy from a wave while minimizing energy loss from design shortcomings.